T-fitting for aircraft antennas



0a. 6, 1910 w. c. meal-#8 3,532,805

' T-FIT'IING FOR AIRCRAFT ANTENNAS Filed March 21, 1969 INVENTOR WILLIAM C. ROGERS Ame, m g

ATTORNEY/S.

United States Patent Office 3,532,805 Patented Oct. 6, 1970 3,532,805 T-FITTING FOR AIRCRAFT ANTENNAS William C. Rogers, 5365 NW. 36th St.,' Miami Springs, Fla. 33166 Filed Mar. 21, 1969, Ser. No. 809,284 Int. Cl. H01b 17/16; H01q 1/12 U.S. Cl. 174-156 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to antenna fittings and more particularly to T-fittings for airplane antennas.

External wire antennas are utilized today in many applications on both light and heavy aircraft both to receive and to transmit information by radio waves. These wire antennas are externally mounted on the aircraft by means of antenna fittings in various configurations depending on the design of the aircraft and the purpose for which the antenna is to be employed. These antenna fittings must, of course, be specially adapted and designed to firmly retain and support the wire antennas in the desired configuration. Since the wavelength of the radio wave energy dictates the length of the antenna, long wires are often required. And of course the forces to which the antenna fittings are subjected increase with the length of the antenna. These fittings must therefore be capable of withstanding mechanical forces of a considerable magnitude.

In addition, due to increasing air traffic congestion the clarity of radio wave transmission is becoming increasingly important. Therefore, these fittings must be specially designed to reduce the accumulation of static charge which causes noise or static interference in the transmission of radio waves.

Many configurations of these external aircraft wire antennas require fittings to support and to retain both an intermediate portion of a first wire antenna and the end portion of a second wire antenna which may be electrically connected thereto. Alternatively, the configuration may require that a lead wire be electrically connected to the first wire antenna at a point intermediate its length. Still other antenna configurations may require that the ends of three wire antennas be electrically connected and supported at a common point on the aircraft. Fittings of this type are commonly referred to as T-fittings.

Prior art T-fittings usually include two coaxial and oppositely extending arms and a third arm perpendicular thereto, each arm having appropriate wire antenna receiving means. These prior art T-fittings generally are utilized only to connect antennas and/or lead wires together and not to support, retain or secure the antennas to the external surface of the aircraft.

Furthermore, since the opposite antenna receiving means in known T-fittings are generally coaxial, these known T- fittings are not practical for use in V-shaped antenna configurations. For example, an antenna wire might extend from the end of one wing to the vertical stabilizer and thereafter to the end of the other wing. A T-fitting may be necessary to mount the antenna to the'vertical stabilizer while interconnecting a second antenna extending along the aircraft fuselage. Alternatively, it may be desirable to connect a lead wire to the V-antenna at that position for balanced dipole operation, for example.

It is, therefore, an object of this invention to provide a novel antenna T-fitting which overcomes or minimizes the disadvantages of previously known antenna fittings of this type and which is suitable for mechanically supporting and electrically connecting two or more wires intersecting over a wide range of angles of the wires with respect to the axis of the fitting.

It is another object of this invention to provide a novel antenna T-fitting for firmly and securely supporting a V- shaped antenna at its apex while also providing means for attaching a lead or second antenna thereto.

It is still another object of this invention to provide a novel and compact antenna T-fitting which reduces the accumulation of static charge on the antenna.

These and other objects and advantages are accomplished in accordance with this invention by a streamlined antenna T-fitting which includes mounting means at one end for securing the antenna to a aircraft and antenna re ceiving means at the other end for supporting and securely retaining the wire antennas and/ or lead wires. The antenna receiving means includes a generally U-shaped channel extending from one side of the fitting to the other side at the ends thereof, and an axially extending channel extending from the end of the fitting to the base of the U- shaped channel. The diameter of the U-shaped channel may be enlarged at the junction of the U-shaped and axial channels to accommodate the electrical interconnection of one wire antenna or lead wire disposed in the axial channel to a second wire antenna disposed in the U-shaped channel. The antenna receiving means is longitudinally split in the place of the channels to facilitate installation and the mechanical retention of the wire antennas in the fitting.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the invention is illustrated in the accompanying drawings in which:

FIGS. 1, 2 and 3 are top, front and rear views respectively of a preferred embodiment of the present invention, and

FIG. 4 is an exploded pictorial view of the preferred embodiment of FIGS. 1, 2 and 3.

FIG. 5 is a schematic drawing illustrating one antenna configuration to which the present invention is particularly adapted.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, 2 and 3 of the drawings, the antenna T-fitting of the present invention may be formed in a conventional manner from a suitable insulating material and includes a central cylindrical portion 10. The cylindrical portion 10 terminates at one end 11 in a generally cylindrical mounting means 12 which may be internally or externally adapted to be threadably secured to a turnbuckle, swivel, hook or other conventional fastening means (not shown) affixed to the external surface of the aircraft. The mounting means may be electrically conductive or insulative as may the housing 10.

The other end 13 of the cylindrical portion 10 flares outwardly in one plane to form the wire receiving means 14. The shape of the wire receiving means 14 is generally that of an isosceles triangular prism with parallel triangular planar faces 16 and 18 spaced apart a distance equal to the diameter of the cylindrical portion 10. The triangular planar faces 16 and 18 are contiguous at the apex opposite the base thereof to present a continuous smooth external surface with the cylindrical portion 10. The edges 20 and 22 between the planar faces 16 and 18 of the triangular wire receiving means 14 are arcuate with respect to the longitudinal axis of the T- 3 fitting and at the wire receiving end with respect to an axis perpendicular to the planar faces 16 and 18. The apices at the base of the planar faces 16 and 18 are thus cut away to form end portions 24 and 26 respectively of the edges and 22. The end surface 28 of the receiving means 14 is substantially normal to the axis of the fitting and is defined by the bases of the triangular faces 16 and 18 and the curved end portions 24 and 26 of the edges 20 and 22.

The wire receiving means 14 includes a generally U- shaped channel extending between the junctions of the two end portions 24 and 26 of the edges 20 and 22 with the surface 28. The channel 30 is substantially circular in cross section with the axis thereof in the median plane of the fitting parallel to the planar surfaces 16 and 18. A channel 32 in the same median plane extends from the central portion of the end surface 28 along the longitudinal axis of the fitting and communicates with the U-shaped channel 30 at its base. The U-shaped channel 30 may be enlarged at the junction 34 of the channels 30 and 32 to accommodate the electrical and mechanical interconnection of one wire antenna or antennas disposed in the U-shaped channel 30 with a second antenna or lead wire disposed in the longitudinal channel 32.

A high degree of flexibility in the use of the fitting with various antenna configurations is achieved by the termination of the U-shaped channel 30 in wide, smoothly curving, openings at the junction of the end portions 24 and 26 of the edges 20 and 22 with the end surface 28.

The antenna wire may enter the fitting at any one of a P wide range of angles with respect to the axis of the fitting Without mechanically crimping the antenna wire. Additionally, the transition of the fitting to the antenna wire is smooth over a wide range of angles of the wire antennas with respect to the axis of the fitting. The problem of the static electricity and corona discharge are thus reduced.

Referring to FIG. 4, the wire receiving means 14 is split longitudinally along the median plane of the fitting parallel to the triangular surfaces 16 and 18 from a line 58 parallel to the base thereof near the opposite apex. A detachable portion 42 is thus formed which may be removably secured to the remaining and major portion of the fitting by means of suitable securing means, for example, threaded screws 38 each of which may extend through an aperture 52 in the removable portion 42 into internally threaded apertures 48 in the upper surface 46 of the major portion 44 of the fitting.

The channels 30 and 32 are formed by complementary grooves provided respectively on the mating surfaces 51 and 46 of the removable portion 42 and the major portion 44 of the wire receiving means 14.

As illustrated in FIG. 4, a through wire 54 may be disposed in the U-shaped channel 30. This through wire 54 may constitute, for example, an antenna wire extending from the end of one of the wings of the aircraft to the vertical stabilizer thereof, and thereafter to the end of the other wing. The axially extending channel 32 may receive an antenna wire or lead wire 56 which is interconnected both electrically and mechanically to the antenna wire 54 by conventional means, e.g., by wrapping and soldering or by the connection of the free end of the wire to the housing 10 with a suitable threaded fastener. A ground connection may thus be established if desired. The enlargement of this interconnection may be accommodated by the enlarged area 34 in the base of the U-shaped channel 30 In utilizing the fitting of the present invention, the wires 54 and 56 will be interconnected and thereafter placed in the channels 30' and 32 in the surface 46 of the major portion 44 of the fitting. The cooperating removable portion 42 of the fitting may then be positioned and secured to the base portion 44 by means of the screws 38.

The diameter of the channels 30 and 32 is preferably slightly less than that of the wires 54 and 56 so that the wires 54 and 56 may be tightly gripped thereby to mechanically support and retain the antenna wires in the fitting. The tension on the electrical and mechanical interconnection of the wires 54 and 56 thus may be materially lessened.

The antenna T-fitting of the present invention is not only suitable for use in V-shaped configuration alone but also for connecting a second antenna wire or lead wire to the antenna while securely retaining and supporting both. The streamlined shape is effective in reducing the buildup of static charge and accompanying corona discharge, yet is provided with surfaces on the wire receiving means. These planar surfaces greatly facilitate the handling and the assembly of the fitting.

As illustrated in FIG. 5, a single wire antenna 60 may be installed from one wing 62 of an aircraft 64 to the other wing 66 by way of the vertical stabilizer 68. The T-fitting 70 of the present invention may be secured to the vertical stabilizer 68 to mechanically support the antenna 60. A lead wire 72 may be mechanically and electrically secured to the antenna 60 at the center thereof by means of the novel T-fitting 70 to couple electromagnetic wave energy from the antenna 60 to a transmitter and/or receiver in the fuselage 74 of the aircraft 64.

The reduced diameter and aerodynamically clean, smoothly curved surfaces of the T-fitting of the present invention offer many disadvantages. Among these advantages are less air resistance and less accumulation of electric charges required in flying through rain, snow, sand, dust or regions of electrical activity in the atmosphere. The smooth surfaces allow the electric charge to travel to static discharge units by way of the metallic skin of the aircraft. Corona discharge and the resultant induction of radio noise voltages into the antenna system are thus minimized.

Although the invention is described with reference to a preferred embodiment it will be apparent to those skilled in the art that other embodiments not specifically described or illustrated may be made without departing from the scope of the inventinn as defined by the appended claims.

I claim:

1. A T-fitting for providing for the electrical interconnection and mechanical support of an external aircraft antenna comprising:

an elongated body generally rounded and free of sharp corners to reduce corona discharge when supported on the body of an aircraft, said body having two parts,

one of said parts having mounting means at one end thereof adapted to mechanically secure the fitting to an aircraft, and wire receiving means at the other end thereof,

said wire receiving means comprising an internal, generally U-shaped channel opening at the said other end of the fitting adjacent opposite sides thereof and a second internal channel extending along the axis of the body to communicate with said U-shaped channel at the base thereof and opening at said other end of the fitting intermediate the openings of said U- shaped channel, and

the other of said parts being detachable from said one part to expose said internal channels.

2. The T-fitting of claim 1 wherein said U-shaped and axial channels are substantially coplanar and wherein the cross sectional area of the U-shaped channel is enlarged at the intersection thereof and said axially extending channel to accommodate the mechanical interconnection of the wires to be disposed in said channels.

3. The T-fitting of claim 1 wherein the dimension of said wire receiving means is substantially unifrom in one plane normal to the axis of the fitting to form substantially parallel top and bottom walls, wherein the dimension of the fitting in a second plane normal to said one plane and the axis of the fitting generally increases from said one end towards said other end of the fitting, and wherein the side walls between said top and bottom Walls are generally areuate about the axis of the fitting.

4. The T-fitting of claim 3, wherein said top and bottom walls are generally triangular in configuration having an apex adjacent said one end of the fitting and a base defined by said other end of the fitting, wherein said side walls are curved inwardly toward the axis of the fitting over a portion adjacent said other end of the fitting, and wherein said U-shaped channel opens into the inwardly curved portion of said side walls whereby a wire disposed therein may assume a Wide range of angles relative to the axis of the fitting without restriction by the housing.

6 5. The T-fitting of claim 4, includes at least three threaded fasteners passing through said top wall for securing said parts, one of said fasteners being located between stid axial channel and each of the arms of said U-shaped channel.

References Cited FOREIGN PATENTS 11/ 1960 Germany.

4/ 1928 Italy.

LARAMIE E. ASKIN, Primary Examiner US. Cl. X.R. 

